Manufacture of airplane frames, etc.



Jqne 19, 1945. A. FENER 2,378,759

MANUFACTURE OF AIRPLANE FRAMES, ETC

Filed Marsh 2., 1943 INVENTOR ATTORNEY Patented Julie 19, 1945 2,378,759MANUFACTURE og i mrmnn FRAMES,

UNITED STATES PATENT OFFICE.

Abe Fener, Bronx, N. Y., assignor to Clara Fener, New York, N. Y.

Application March 2, 1943, Serial No. 477,701

3 Claims. (Cl. 153-32) This invention relates to the fabrication ofairplane structural parts. More particularly my invention is directed toan improved process for shaping and fitting a finished frame unitinaccordance with a template or jig.

The process for fabricating airplane frame units generally includesheat-treating such units by dipping them into a chemical bath fortoughening purposes, or by treating them in other suitable well knownways, with the result that these frame units become distorted from theirnormal desired shape and cannot be properly assembled. It is thereforenecessary to restore these distorted frame units to their desired shapein accordance with a template or jig. The method heretofore employed forshaping th distorted frame units consisted in hammering' the unit tothereby force it into shape. 'lhisformer method contained many inherentdisadvantages among which were the following: Since these airplane frameunits generally comprised flanges along the longitudinal edges thereofand cut out or notched edge portions which are known as stringer restsdesigned to accommodate the stringers used in the assembly of the framesinto the airplane, in a large proportion of the cases processed by theold method the frame units would split or crack in the area of thesestringer rests mer since it was the weakest parts of the frame unitstructure. As a result the cracked frame unit had to be scrapped. Thisrepresented a great loss of time and material and retarded the speed ofproduction so vitally necessary in war times. The applicant is aware ofone plant, in which the above described hammering method of restoringthe frame units was employed, where out of twenty frame units completedby one man in one day, as much as fifteen frame units were rejected bythe inspector and junked as cracked .or broken.

Another-disadvantage of the frame fitting or shape restoring process asheretofore practiced was that due to the fact that by repeated hammerblows on the material, certain areas thereof became thinner than others,thereby greatly weakening the frame and rendering it unsafe for use.

It is therefore one of the principal objects of my invention to providea highly improved, yet simple, process for restoring or otherwiseshaping airplane frame units so as to eliminate the above describeddisadvantages and which shall at the same time be attended withadditional advantages as will hereinafter become apparent.

when struck with a hamduring such treatment the frame units become unitthe said frame This application is a continuation-in-part of mycopending application Serial No. 444,154, filed May 22, 1942, forManufacture of airplane frames, etc. Y

In the accompanying drawing in which is shown an embodiment of myinvention:

Fig. ,1 is a side elevational view of one type of airplane frame unitupon which the: process of my invention is practiced;

Fig. 2 is an edge elevational view thereof;

a Fig. 3 is a side elevational view of the frame shown in Fig. 1, butillustrating the same supported in accordance with my invention;

Fig. 4 is a top plan view thereof;

Fig. 5 is a view similar to Fig. 3, but illustrating a further step inmy improved process;

Fig. 6 is an enlarged cross-sectional view taken substantially along theline 6-6 of Fig. 5; and

Fig. 7 is an enlarged cross-sectional view taken substantially along theline 1-1 of Fig. 5.

Referring now in detail to the drawing I have shown therein for thepurposes of illustration 8. frame unit I!) of the type employed in thefabrication of airplane frames, but which may be of any customary shapeor design. The frame unit, is generally proyided with continuous nangesll along the longitudinal edges thereof with the exception ofcertain'areas, such as for example at l2 to 20 where there is aninterruption in the continuity of a portion of the flanges II. It isalso noted that adjacent these said areas I2 to 20, the frame unit isnotched inwardly from the edge thereof to provide rests for thestringers ultimately used in the assembly of the frames. These stringerrests may be of any shape consistent with the design of the airplane.

As explained above, these frame units II) are heat treated or otherwisetreated for toughening the frames or for any other desired reasons, and

misshapen or distorted.

In accordance with the following process for restoring or otherwiseshaping the distorted frame units without spoiling or otherwiserendering the frame unit unfit or unsafe for use.

I first position a pair of blocks 26 and 21 on opposite sides of theframe unit In and between the flanges II, which may be disposed as tooverlie the stringer rest l2, and rigidly secure unit and blocks in asuitable such as, for example, between vise 20. The frame unit I0 isholding means, the laws of a my invention, I provide outwardly.

made of wood, but

preferably supported in thevise 20 at a point approximately near thecenter thereof with opposite ends of the said unit I!) freely projectingI then position a second pair of members '32 and 33 on opposite sides ofthe frame unit I, adjacent the flange and in the vicinity of andoverlying opposite sides of another one of the notched areas, such asfor example the area l3. These blocks 32 and 33 are maintained inposition by suitable clamping means such as, for example, the clamp 35,as shown in Fig. 6 of the draw.

relatively rigid block ing. I then position a third pair of blocks 31,38

on opposite sides of the frame [and overlying the stringer rest 14. Aclamp 35 holds these blocks 31 and 38 in position. I now correct orrestore that portion of the frame unit l in the area where the pairs ofblocks 26, 21, 32, 33 and 31, 38 ar positioned, by bending, pulling,pushing or twisting the frame, manually if desired, to conform to adesired template or jig. The said clamped pairs of blocks preventcracking or breaking of the frame unit at its vulnerable points adjacentthe said notched areas l2, l3 and M by preventing too sudden or sharp abend and by distributing the bending, pushing or twisting forcesapplied. It is particularly noted that this restoring process has beenaccomplished without resorting to violent hammer blows. I have foundthat good results are obtained when the said block members are longerthan the notches which they overlie.

In accordance with my invention, I have found that when three sets ofblock members are clamped in position covering three adjacently disposednotches or stringerrests, I obtain excellent results when working in thegeneral area of the said three stringer rests. But it is understood,however, that any other desired number of pairsof .blocks may beemployed and disposed in any other desired arrangement.

I have found that I obtain good results when the block members 26, 21;32, 33 and 31, 38 are it is understood that they may be made of anyother known material suitable for the purposes set forth. p

In accordance with the provisions of the patent Y and practice of myoutlined, and the invention extends to described the principleinvention, together with the best apparatus or steps which I nowconsider to represent the best embodiments thereof, but I desire to haveit understood that the apparatus shown is only illustrative and that theinvention can .be practiced by other apparatus, also, while it isdesigned to use the various features and steps in the combination andrelation described, some of these may be altered'and others omittedwithout interfering with the more general results statutes, I haveherein Having described my invention, what I claim and desire to secureby Letters Patent is:

1. In the process frames for fuselage or wing construction wherein afinished frame unit, having certain areas thereof weakened by notchedspaced stringer rest portions, is treated for toughening Or for otherpurposes and in which the said treatment causes distortion of the saidframe unit from its desired shape-that improvement for restoring thesaid distorted frame unit to its desired shape which comprises the stepsof positioning a pair of blocks on opposite sides of said frame unit andclamping the said blocks and frame unit in a vise member to support thesame with opposite ends thereof projecting freely beyond raid vise,positioning one or more pairs of rigid members on opposite sides of saidframe unit and substantially bridging said notched stringer restportions, supporting said rigid members solely by said freely projectingportions by clamping said pairs of rigid members in position and thenexerting a pushing, pulling or twisting force on said frame, in the areaof said two adjacent stringer rest portions to restore its shape inaccordance with a template or jig.

2. A process for manufacturing airplane frames or the like according toclaim 1 in which the said rigid members preferably have a degree ofrigidity on the nature of wooden blocks.

3. The process of manufacturing airplane claim 1- in which twistingforce is ABE FENER.

such use.

of manufacturing airplane

